This invention relates to solenoid operated fluid valves and more particularly to electronic circuitry for controlling the operation of such valves.
Commercially available single-acting, solenoid operated valves normally have two external circuit connections for each coil including a source or positive connection and a ground connection. In a double-acting valve there are normally two solenoid coils with appropriate connections provided.
Production machines frequently utilize several such valves. For example, in double flier armature winding machines there may be on the order of 15-20 solenoid operated fluid valves. Conventionally the valves are remote from the circuitry which controls the energization of the valves.
Increased reliability, ease of maintenance and economies of manufacture are among benefits that can be obtained by converting the more conventional control circuits for machines such as automatic armature winding machines to circuits utilizing solid state components including integrated circuit control logic. To minimize the power required to operate such machines it is desirable that the valve controls or the like be operated at minimal power levels. However, noise resulting from the operation of the various components of the machine and especially the voltage spikes created upon collapse of the solenoid coils, if transmitted from the valves to the control circuit elements, may cause ill-timed or unwanted operation of one or more of the valves.
Another problem experienced primarily with AC operated double-acting valves is that both coils within the valve housing may be inadvertently simultaneously energized. As a result the coils of such valves are often burned out.
The primary object of this invention is to provide an improved solenoid operated fluid valve especially adapted for use with solid state control systems in production machinery or the like wherein a number of such valves are used. The following patents are considered to be reasonably representative of the prior art relating to such valves:
3,790,127 3,709,253 3,659,631 3,580,504 2,599,862 2,759,429